livepatch: x86: fix relocation computation with kASLR

With kASLR enabled, old_addr provided by patch module is being shifted
accrodingly so that the symbol lookups work. To have module relocations
handled properly as well, the same transformation needs to be perfomed
on relocation address information.

[jkosina@suse.cz: extended / reworded changelog a bit]
Reported-by: Cyril B. <cbay@alwaysdata.com>
Signed-off-by: Zhou Chengming <zhouchengming1@huawei.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 6e5344112419ca43ace3474466db35d1692752ab..db545cbcdb8933e1ab4b95a9c276eb523de8ba43 100644 (file)
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -294,6 +294,12 @@ static int klp_write_object_relocations(struct module *pmod,
 
        for (reloc = obj->relocs; reloc->name; reloc++) {
                if (!klp_is_module(obj)) {
+
+#if defined(CONFIG_RANDOMIZE_BASE)
+                       /* If KASLR has been enabled, adjust old value accordingly */
+                       if (kaslr_enabled())
+                               reloc->val += kaslr_offset();
+#endif
                        ret = klp_verify_vmlinux_symbol(reloc->name,
                                                        reloc->val);
                        if (ret)